Solve the equation P=k x t / V for the letter k

Find vertex of f(x)=x^2+6x+10

dem82 [27]

You can see answer at photo! If you have any questions, write me in Telegram @ef1m0ff

5 0

3 years ago

Answer this quick I have 20 minutes 25 points

e-lub [12.9K]

The answer is A. You can comment if u want an explanation :)

6 0

3 years ago

f) The life of a power transmission tower is exponentially distributed, with mean life 25 years. If three towers, operated indep

Step2247 [10]

Answer:

15.24% probability that at least 2 will still stand after 35 years

Step-by-step explanation:

To solve this question, we need to understand the binomial distribution and the exponential distribution.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

In which $C_{n,x}$ is the number of different combinations of x objects from a set of n elements, given by the following formula.

$C_{n,x} = \frac{n!}{x!(n-x)!}$

And p is the probability of X happening.

Exponential distribution:

The exponential probability distribution, with mean m, is described by the following equation:

$f(x) = \mu e^{-\mu x}$

In which $\mu = \frac{1}{m}$ is the decay parameter.

The probability that x is lower or equal to a is given by:

$P(X \leq x) = \int\limits^a_0 {f(x)} \, dx$

Which has the following solution:

$P(X \leq x) = 1 - e^{-\mu x}$

The probability of finding a value higher than x is:

$P(X > x) = 1 - P(X \leq x) = 1 - (1 - e^{-\mu x}) = e^{-\mu x}$

Probability of a single tower being standing after 35 years:

Single tower, so exponential.

Mean of 25 years, so $m = 25, \mu = \frac{1}{25} = 0.04$

We have to find $P(X > 35)$

$P(X > 35) = 1 - P(X \leq x) = 1 - (1 - e^{-\mu x}) = e^{-0.04*35} = 0.2466$

What is the probability that at least 2 will still stand after 35 years?

Now binomial.

Each tower has a 0.2466 probability of being standing after 35 years, so $p = 0.2466$

3 towers, so $n = 3$

We have to find:

$P(X \geq 2) = P(X = 2) + P(X = 3)$

In which

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 2) = C_{3,2}.(0.2466)^{2}.(0.7534)^{1} = 0.1374$

$P(X = 3) = C_{3,3}.(0.2466)^{3}.(0.7534)^{0} = 0.0150$

$P(X \geq 2) = P(X = 2) + P(X = 3) = 0.1374 + 0.0150 = 0.1524$

15.24% probability that at least 2 will still stand after 35 years

4 0

3 years ago

How many numbers are in the list 2008, 2003, 1998,............. 8, 3?

Helga [31]

Answer:

I don't understand what you are trying to ask? Sorry

5 0

3 years ago

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3(x-7)+8=-20 can someone explain how to do this step by step

Mrrafil [7]

3(x-7)+8=-20

Multiply the bracket by 3

(3)(x)(3(-7)+8= -20

3x-21+8= -20

3x-13= -20

Move -13 to the other side. Sign changes from -13 to +13.

3x-13+13= -20+13

3x= -7

Divide by 3

3x/3= -7/3

x= -7/3 or in mixed number : -2 1/3

Answer : x= -7/3 or in mixed number : -2 1/3

3 0

3 years ago

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